12th International Symposium on District Heating and Cooling

The <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, EstoniaDISTRIBUTION OF HEAT USE IN SWEDENMargaretha Borgström, Sven Werner1 School of Business and EngineeringHalmstad University, PO box 823, S-301 18 Halmstad SwedenABSTRACTThe current heat use refers normally to the averageheat use in a country or a sector during the course of ayear. But it is also important to be aware of thedistribution of high to low use when estimating thepotential for reducing total heat use.Energy statistical data published in the annual reportfrom Statistics Sweden have been supplemented by adeeper analysis of distribution of heat use andsystematic causes regarding high heat use.The aim of this paper is to explain the variation in heatuse with respect to construction year, degree days andenergy efficiency measures.In the Swedish energy efficiency debate, many voicesrefer to systematic causes for high heat use. However,the results from this study do not support this opinion,since the use distribution mostly comes from individualcauses. The most important implication of the studyresults is that systematic policy measures will have alow impact on the total national energy efficiency.INTRODUCTIONcorresponding to 310 million square metres in multifamilybuildings and service sector premises. Thesurvey sample thus constituted a sizable portion of theentire building stock.This energy statistical data, published in the annualreports from Statistics Sweden, have beensupplemented with a deeper analysis of the distributionof the heat use and the systematic causes regardinghigh heat use. Independent variables for explanation ofvariations were number of degree-days, constructionyear, ventilation system, energy efficiency measure,and co-use of heat supply. High and low users werealso analysed by location, construction year, heatsupply method, ownership, and building size [3]. In thisshort paper, the specific heat use will be presented byits distribution, construction year, degree days andenergy efficiency measures.1. Distribution of heat useThe total distribution of specific heat use as a functionof the percentage of the building area of all multi-familybuildings and service sector premises in Sweden isshown in Fig. 1.Multi-family residential buildings and service sectorpremises constitute 80% of the customer stock in theSwedish district heating systems. The level of futureheat use in these buildings will thus have a stronginfluence on the future district heating economy and thecorresponding investment demand. It is therefore ofinterest to collect information and make analyses of thecostumer heat use and how the heat use will develop inthe future.Specific heat use in multi-family buildings and servicesector premises has decreased considerably since the1970‘s. In 2006, the specific heat use in multi-familybuildings has decreased by 38% compared to the heatuse in 1972. The lower heat use is due to increasingenergy prices and more energy efficient buildings.An extensive study of the current heat use for buildingsin Sweden has been performed. The input informationfor this study was constituted by the anonymousresponses to the annual survey of energy use in multifamilybuildings and service sector premises performedfor 2006 by Statistics Sweden, [1] & [2]. The responsesprovided input data from 11253 buildings having a totalarea of 77.6 million square metres. By using scalingfactors, estimates could be made for the entire country,273Heat usekWh/m 240035030025020015010050Multi-family buildingsPremises00% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%Share of all national building spaceFig. 1 Heat use distribution during 2006 as a function ofthe share of all national building space. The diagram is anestimation for all multi-family and service buildings inSweden.The area under each curve is the total heat used inmulti-family buildings and service sector premisesduring 2006. The figure shows that 13% of the area inmulti-family buildings had a specific heat use of morethan 200 kWh/m 2 , and 12% of the area in servicesector premises had a specific heat use of more than200 kWh/m 2 . This result shows that there are no majordifferences between the percentages of the building